A traveling control system for a construction machine in the related art, as illustrated in FIGS. 1A and 1B, includes first and second hydraulic pumps P1 and P2, connected to an engine (not illustrated), a left traveling control valve 2 installed in a discharge flow path 1 of the first hydraulic pump P1 to control driving of a left traveling motor, a first working device control valve 3 installed in a parallel flow path 1a of the first hydraulic pump P1 and composed of spools that control driving of a first arm and a second boom, respectively, a right traveling control valve 5 installed in a discharge flow path 4 of the second hydraulic pump P2 to control driving of a right traveling motor, a second working device control valve 7 installed in a parallel flow path 4a of the second hydraulic pump P2 and composed of spools that control driving of a first boom, a bucket, and a second arm, respectively, a traveling switching valve 8 installed in the parallel flow path 1a of the first hydraulic pump P2 and the discharge flow path 4 of the second hydraulic pump P2 and switched to distribute and supply hydraulic fluid from the first hydraulic pump P1 to the left traveling motor and the right traveling motor and to distribute and supply hydraulic fluid from the second hydraulic pump P2 to the first working device control valve 3 and the second working device control valve 7 so as to prevent eccentric traveling, and an electronic valve 9 switching the traveling switching valve 8 to a traveling switching mode during a combined operation in which traveling and working devices are simultaneously operated.
As illustrated in FIG. 2, in the case of performing inlay work for smoothing the ground or carrying heavy objects using an excavator, an operator simultaneously operates a working device 10, such as a boom or an arm, and a traveling device (indicated as a track in the drawing) 6.
That is, in the case where the operator operates the working device 10 through an operation of a joystick and simultaneously operates the traveling device 6 through an operation of a traveling pedal to perform inlay work, the traveling switching valve 8 is switched to a traveling switching mode (spool is shifted to the position of FIG. 1B) by the electronic valve 9. Through this, hydraulic fluid that is discharged from the first hydraulic pump P1 is distributed and supplied to the left traveling motor and the right traveling motor through the discharge flow paths 1 and 4, and hydraulic fluid that is discharged from the second hydraulic pump P2 is distributed and supplied to the first working device control valve 3 and the second working device control valve 7 through the parallel flow paths 1a and 4a. 
Accordingly, in the case of performing the smoothing work through simultaneous operation of the working device during traveling, eccentric traveling of the equipment can be prevented.
On the other hand, if the operation of the working device 10 such as an arm is instantaneously stopped (as an example, if an arm-out operation is performed for the smoothing work after an arm-in operation) in the case of the simultaneous operation of the working device 10 during the traveling (indicated as rightward traveling in FIG. 2), the traveling switching mode function of the traveling switching valve 8 is released.
As described above, since the traveling switching mode function of the traveling switching valve 8 is released (spool is shifted to the position of FIG. 1A) at a moment when the operation direction of the working device such as an arm is changed during the traveling of the excavator, shock occurs when the working device 10 is operated, and this may cause operator's fatigue to be increased and operability of the working device 10 to deteriorate.